D means that the product is rated in its category in terms of energy efficiency. The Energy Labeling system is based on EU Regulation 2017/1369/EU. D Lenovo L24m-4A, 23.8", 1920 x 1080 pixels, Full HD, LED, 6 ms, Gray Lenovo L24m-4A. Display diagonal: 23.8", Display resolution: 1920 x 1080 pixels, HD type: Full HD, Display technology: LED, Response time: 6 ms, Native aspect ratio: 16:9, Viewing angle, horizontal: 178°, Viewing angle, vertical: 178°. Built-in speaker(s). Built-in USB hub, USB hub version: 3.2 Gen 1 (3.1 Gen 1). VESA mounting, Height adjustment. Product color: Gray